This chapter discusses basic microstructural concepts and discontinuity formation, as they relate to laser processing. It outlines the major microstructural zones that occur in the part during processing, addressing the fusion zone, zone of partial melting, and the heat‐affected zone (HAZ). The processes that involve fusion have four distinct zones in the region where the heat is applied. These are as follows: fusion zone, zone of partial melting, HAZ, and base material. Discontinuities are normally introduced into a part during processing. There are various types of discontinuities, and the principal ones include porosity and cracking, which are metallurgical; incomplete penetration, lack of fusion, and undercutting, which are process‐ and technique‐related. Solidification in the fusion zone involves nucleation and growth. The concept of epitaxial solidification, which is common with laser processes that result in melting without the addition of filler material, involves solidification without nucleation.
The Microstructure
2023-02-07
34 pages
Article/Chapter (Book)
Electronic Resource
English